Oris 150

BD Design


As with all my projects and ideas: plenty of ideas but no projects... But if I finally DO build something, it is destined to be outdated within a year. And so it passed that my "not-even-painted" Lowther BelCantos had to make way for a new design.

It all really started the day I bought my PM2A's from Bert Doppenberg. I had a listening session with a set of Fidelios I think they were.


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listening session at Bert's house

I liked the overall sound of Lowther, but the Fidelio was not my thing; just too little body to make it all believable. This left me with really one still affordable option, and it was called BelCanto. This would only cost me the two PM2A units and a pile of wood which I could get for not all too much at the local home-and-garden stores. The result of my effort can be seen on the BelCanto page...

The damnedest thing was that Bert showed me his own system just after listening to the Fidelios. At the time his set consisted of a set of the weirdest looking square "horns". About half an hour later I found out that the bass was coming from a pair of behemoth horns buried underneath the living room floor. And here I thought the BelCantos were already on the edge. I sat down in a comfortable chair positioned just right so that I could listen to the music and just dream away.


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Bert's original front horns

During the last two years I stayed in contact with Bert and occasionally dropped by for a visit and a listening session. I was amazed at the front horn system and what it could do with the music. The BelCanto was very open en direct, very detailed and fresh. The front horn system had better positioning and a better image, the only thing that bugged me was the fact that the sound was very "closed-in", not as open as the BelCanto. It really came down to which you preferred most, and Bert preferred this over the more open cabinet speakers.

In the summer of '98 Bert made a listening studio in his back yard, I think his wife and kids got tired of his hobby and threw his horns out ;))) This extra space went to Bert's head and he started to experiment with his front horns. He put a plaster-of-paris layer over the surface of the front horn in order to try and get a different sound. He also shortened the throat of the horn. This was not really to his satisfaction and he put the horns next the trash bin. "Hey, if you're going to throw them away, can I have them?", and so they were mine to play with. This was my first introduction to the front horn on my own system at home.

Since I didn't have a sub to accompany the front horns (which only play from 200Hz and up) I placed them directly in front of the BelCanto cabinets. You can imagine what that looked like :)  A steam boat comes to mind. This setup was not a great success, but I never thought it would be. It was enough to give me an impression on the overall character of a front horn. I came to the same conclusion as before: the sound was too "closed-in" compared to what I was used to. This was really the only drawback for the front horns.

But Bert wasn't being lazy, he was working on yet another idea to improve his front horns. A rectangular version quickly appeared in his listening room for experiments.


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It looked really slender, not as colossal as the square horns, although they had the same area and depth. It was a floor standing model this time. This cabinet/horn was only present for about two visits, the third time I came around they were already gone. "I have an even better idea!" Bert explained... He had found a company that could make plastic forms and this led him to design his now well-known round front horns, the Oris 150.

Listening to his new horns, the first thing I immediately noticed was that the annoying little characteristic of sounding "closed-in" was gone. Wow... He finally did it... This was finally a system I could enjoy even more than my BelCantos. After some talking and a few visits later I was able to buy Bert's demo set of front horns. Now I could try them out myself and see what I thought of them.

I took them home and immediately started to hook them up. I still didn't have a sub for the bass, so I stole back my old speakers (Visaton VIB 2 extra) and used them as the sub woofers. I was hooked right away... Sure, the system was not optimal (far from it), but I now had a goal. A few weeks later I bought a sub cabinet that Bert had made to go with the front horns. It was a reflex cabinet (very heavy!) using a 10" Vifa woofer. I have been using only one sub cabinet, mono, until recently.

As things always go with Bert, he came up with some modifications to further improve the Oris system. A renewed pipe to house the Lowther, new dampening material etc etc. He now also has the horns made in series and they look much better than the demo pair I had. All factors added up meant I wanted the final version for both sound and looks. Now what to do with the old speakers... what any other DIY'er would do: trade them for tubes :))))  Mattijs de Vries, another front horn lover, traded with me and now own Bert's round Oris horns as well.

Only in April 2000 did I scrounge together enough mullah to afford the new Oris 150 horns. Bert generously assembled a pair for me on the spot so I could take them home with me the same day. Surprisingly, when I left to go home I somehow ended up having bought new magnets for my PM2A's as well. I don't know how Bert did it, but he somehow made me upgrade to PM4A along with buying the front horns. Wow... this means I really am DONE with my speaker system finally. :)))

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Lowther PM4A next to a UX171A to show the size.


Not much has changed (or remained changed) all this time. I'm still using the Oris 150 along with the LaScalas. The results of the Oris 103C project have led me back to using the Oris 150. The only change is that I will be changing the PM4A that I have right now to AER units. More on that later though.


So, where was I ?  Well, I just traded in my Lowther PM4A's for a pair of AER units. The choice was the obvious next step for me, but the form of the new driver was not. The AER cone sounds a lot better than the standard Lowther cone. It has much more detail and HF response, which is what I needed. Listening to 15-16kHz just didn't cut it anymore. My experiment with the Altec 291 compression driver left me very disappointed with that approach, so I am sticking to my two-way system for now. 

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Beside the cone it was also possible to use different types of magnets: mk1 ferrite, PM2, PM4, DX3 or DX4. As I prefer the heavy magnets my options were really between the PM4 and AER-Nd types. Bert Doppenberg was gracious enough to experiment with the two different magnets while I was there. We did an AB sort of test; same amp, same channel but different magnets hooked up (mono).


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The PM4 magnet showed real promise in combination with the AER cone. This is what I was after, more so than the standard Lowther PM4A. We then listened to the Nd magnet, hmmm, a lot more detail in the highs. The sticks hitting the cymbals were really snapping, not swishing like with the PM4 magnet. What a difference a magnet makes, eh ?! The Nd magnet is built up of two standard Nd magnets (sort of like the DX4), it is not the standard Nd unit AER has had up to now (like DX3) but a prototype. The path is set. AER with Nd2 magnets.

Along with the new unit I also changed to a somewhat shorter diffuser. The new "nose" looks a bit more civilized (no more Pinocchio!).

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Today I picked up a pair of additions to place on top of the phase plugs in my AER units. I've heard them on Bert's system and found them to be quite an improvement. They make the soundstage less nervous so I don't have to hold my head spastically in one position (called sweet spot). The highs seem more present and not as messy, voices are more potent and the sweet spot has become much less annoying. A welcome addition to my system! 

For more info, visit Bert's site (www.bd-design.nl).

Another thing I found out is that I really need to have my horns painted. The horn itself has a big influence in the sound when it is not painted it appears. When I tap it, it sort of sings for a second or so, the painted version doesn't have this effect. The paint seems to dampen the plastic of the horn so it will not color the sound as much as with a bare horn, such as I have right now. Have to make up my mind then on the color (mint green with yellow stripes?).


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The "crown" installed on top of the phase plugs


23-03-2003, A bit of history

I visited BD-Design this weekend and we had a go at listening to the new BD1 units in the, also new, Oris 200+ horns. Small changes in the x-over with the bass speaker still had to be made, but these speakers are showing real promise already. The sound is cleaner and more open than with the Oris150 (deeper and wider). This makes the normal 150 tuned setup sound a bit cold as the bass does not match the horns yet (small gap since the 150 goes deeper into the lows). Next week things should be solved with the bass and the new BD2 units installed in Bert's system. He also has new chassis he is experimenting with. They have a stiffer suspension which gives them a different character. This was very evident in the session using the new BD1 magnets. The "Flat Spider" chassis got my favour in the Oris200, but it might turn out to be a bit too dull in the 150 system. Definitely a contender to replace my Oris 150 Horns.

PM2A, remnants of the BelCanto, my first venture into full-range (ahem).

PM2A/AER, "I have highs now!", this gave me a wake-up call to the shortcomings of a Lowther cone.

PM4A/AER, upgrade for more control and power.

DX4/AER, upgrade, prefer the highs and subtle differences in character vs. the PM4A

BD2/FS in Oris200, coming soon?



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Setup as it was with the LaScala horns for the bass.
units: Lowther PM4A + Altec 421-8H


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Present situation with Horn/BR bass cabinets.
units: AER Nd2 + Altec 515C

If you would like more info on the Oris front horns or Lowther in general, please
contact Bert Doppenberg or take a look at his site www.bd-design.com